It is known that carbon black can be produced by pyrolytic decomposition of various hydrocarbon feedstocks. The widest use for such carbon blacks is in tires as a reinforcing agent for rubber. The eventual content of very small quantities of carcinogenic materials in the carbon black in these applications does not constitute a problem.
However, if carbon black is to be used either as a food ingredient or only in applications where the material in which it is incorporated gets in contact with food such as in wrapping materials, or rubber hoses or tubes in through which food materials or ingredients intended for human comsumption such as milk are flowing, the product is subject to rigid controls and has to pass certain tests before its use in these applications is approved. One of the problems is that extremely small but still detectible quantities of condensed polynuclear aromatics can be present in certain carbon blacks. Benzo (a) pyrene is an example of a known carcinogenic material among the many condensed aromatic ring structures. It would be desirable to have a process available by which a carbon black beng essentially free of such carcinogenics can be produced. It would be particularly desirable to have a process available by which a non-carcinogenic carbon black is produced which is normal, i.e., not slow curing.